Injectors are devices that expel fluid, such as contrast fluid, into a circulatory system, which is used to enhance medical imaging like for example x-ray or magnetic imaging. The contrast fluid or contrast media is injected from a syringe, through a tube, and into an animal subject or human patient. Injectors are well known for use with a powered injector unit that is frequently fixed to a stand or support. Injectors typically include a plunger drive that couples to the plunger of the syringe and moves the plunger forward to expel fluid into the tube thereby injecting the contrast media in the subject.
Powered injectors or motorized injectors often include circuitry that controls the plunger drive unit for setting the rate of injection and/or the amount of fluid injected. Typically, the control circuitry includes switches which allow a user to manually actuate the drive unit to move the plunger within the syringe. The injector may cycle the plunger through the syringe one or more times to fill the syringe with fluid and expel any air bubbles trapped inside. Other syringes come pre-filled, which reduces the number of plunger drive movements needed to prepare the injector for a new injection. After the procedure has ended, the syringe plunger, typically positioned at the forward end of the syringe barrel, is retracted so that the syringe may be removed from the injector. In some injectors, the syringe can only be removed or replaced while the plunger drive is fully retracted.
Excess contrast media remaining in a syringe after an injection must be discarded as is well known in medical procedures to prevent cross contamination and/or infection. However, contrast media can be expensive. For this reason, when preparing for an injection, an empty syringe is filled with only as much media as will be needed for the next procedure. Similarly, pre-filled syringes are sold in a number of sizes, for example ranging from 60 to 200 milliliters, allowing the operator preparing for an injection to select a syringe containing only as much media as is needed for that procedure. Accordingly, the syringes may have one or more characteristic properties or parameters that if communicated to the power injector would assist the operator in the procedure and provide safeguards for ensuring proper use of the contrast media. Examples of such parameters may include syringe diameter or length, syringe material, contrast fluid composition and concentration of the contrast media. These parameters may affect certain procedures like the delivery rate or pressure.
Some syringes include information encoded into the surface of the syringe. When the syringe is inserted and rotated, the power injector reads and processes the information accordingly. In this situation, customized syringes must be used with a specific power injector. What is needed is an adapter that encodes and provides information to the powered injector unit for generic types of contrast media syringes.